The prior art of balancing a color wheel is directed to two primary methods; the first method is to apply adhesive materials onto a motor or the carrier or to a groove in the carrier of a color wheel. The second method is to drill holes on the carrier in order to balance the color wheel, but difficulties are associated with the second method in controlling the exertion of force, and thus may easily cause damage to the bearing; furthermore, metal powder or particles may contaminate and scrape the coating surface of the color wheel itself, thereby causing defects. In an attempt to solve the shortcomings of this prior art U.S. Pat. No. 6,747,803 incorporated herein by reference in the name of Hung discloses a color wheel that forms a annular groove at the position originally intended for the drilling holes on the external surface of the carrier, so that when the color wheel has an unbalanced rotation, a balancing material, such as glue, is filled into the annular groove instead of drilling holes to attain the effect of balancing the color wheel.
U.S. Pat. No. 6,705,733 incorporated herein by reference to Yu et al. also discloses a system wherein a groove in a washer that rotates with the color wheel is used in a similar manner wherein an adhesive material is placed in the groove to balance the color wheel.
Applying adhesive material to a U shaped or parallel channeled groove within a carrier or washer works adequately, as long as the adhesive remains in the groove. It has been found however, that the adhesive material is subject to a centrifugal force due to the rotary motion of the washer or disk used for balancing and in some instances becomes loose and dislodges from the groove, thereby leaving the color wheel unbalanced.
Therefore, it is an object of this invention to provide a carrier wheel having a groove with a shape that prevents adhesive counter balance applied thereto, or therein, from dislodging and being forced out of the groove as it spins. The shape of the groove is designed to hold the cured adhesive during all normal use while the color wheel is spinning.
It is an object to of the invention to provide a simple and inexpensive solution to the problem of the counter balance becoming dislodged, associated with the prior art.